The City (v27) match definition is a temporary definition provided to facilitate an upgrade of the City definition. The City match definition will be changing in the following way:

In a future release, the match code length will be changed. This change might require you to update any jobs using the City definition so that the match code fields can handle the new length. The City (v27) definition uses the match code length that will be used by City in the future.

If you want to begin using the updated processing now rather than waiting for a later release, you can update your jobs to call the City (v27) definition. Be aware however that the City (v27) definition is deprecated and will be removed in a subsequent release when the City definition is updated.